EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: teconomy on April 18, 2018, 03:09:54 pm
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Hello, I have a Tektronix 222 scope in great condition except the display is rotated. See attached photos.
I have it pulled apart and have the service manual and have tried all the adjustments that I can find but none will correct the issue.
Any thoughts?
Thank you
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This is a CRT so the coil packet could be out of position. I'm no expert but you can look if it can move and try turning it, beware of VERY HIGH voltage inside.
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Hi and thank you for your reply,
I tried to gently turn the base but it appears that it does not rotate. I am reluctant to apply too much torque in fear of breaking it.
Thanks again!
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I don't know much if anything about the 222 scope, but I would agree that it sure looks like the deflection yoke is rotated. There is usually a clamp somewhere on the yoke that needs to be loosed before it can be rotated - did you loosen the clamp?
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I don't know much if anything about the 222 scope, but I would agree that it sure looks like the deflection yoke is rotated. There is usually a clamp somewhere on the yoke that needs to be loosed before it can be rotated - did you loosen the clamp?
It's an electrostatic deflection CRT, so there's no yoke.
OP, what happens when you try to adjust HORIZ ALIGN and VERT ALIGN?
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Many scopes have a trace rotation coil, if this does then it may have become disconnected or whatever drives it has failed.
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I just added an other photo of the interior of the scope.
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When I adjust the HORIZ ALIGN and VERT ALIGN they appear to operate correctly in that they slide the display on the x an y axis respectively. They along with all of the other adjustment pots all appear to work fine however none of them address the issue of rotation.
Thx
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I downloaded a copy of the manual from Tek wiki: http://proxy.w140.com/tekwiki/wiki/222 (http://proxy.w140.com/tekwiki/wiki/222)
I see on page 3-7 in the last paragraph the 222 uses electronic trace rotation. I could imagine that too much of the X is being fed into the Y thus causing a major rotation or lozenging.
I don't seem to see any schematics in the above manual so I can't offer any advice other that to check the values of all resistors near the Horizontal and Vertical align trimpots.
Cheers,
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That sure is a neat little scope, I wish I had one.